This invention relates to a method for executing a reproducible glow discharge process in which the formation of characteristic volatile stable products that are formed during the reaction with a reactant located in the reaction space can be traced mass spectrometrically.
Glow discharge processes are used, among other purposes, in the manufacture of solar cells for the formation as well as the removal of films. For example, promation of a film is known from DE-OS No. 21 52 895, in which the efficiency of a copper-sulphide/cadmium-sulphide thin film solar cell is increased by adding to the copper-sulphide layer another layer containing copper that is thin in comparison to the copper-sulphide layer. During this process, the amount of copper needed for the additional layer can be produced via the reduction of the copper sulphide on the surface, namely, through treatment in a glow discharge in a hydrogen atomsphere. The removal of layers for the manufacture of efficient solar cells is known, for example, in connection with inversion-layer solar cells. Glow processes are also used in cleaning reaction spaces that are used for the manufacture of a-Si solar cells. In this case, the glow discharge serves to clean, the polysilane or polymers of doping gases, such as PH.sub.3 and B.sub.2 H.sub.6, which are present in the react ion space by etching them away with fluorine compounds. Glasses can also be cleaned in a glow process.
The procedural regulation of glow processes, such as continuous and adjusted gas pressure, is based typically on experimental values. Thus without a consistent way of measuring the reaction, glow processeses do not lead to the desired results.